CODEWITHSUNDEEP
c#histogramemgucvopencv3.0mat
Lea
Lea

Reputation: 31

calcHist OpenCV for C# error

I'm trying to calculate an histogram from an image with OpenCV for C# (EmguCV).

This is my code:

        VectorOfMat bgr_planes = new VectorOfMat();
        CvInvoke.Split(myImage, bgr_planes);

        int[] dim = new int[] { 0 };
        int[] histSize = new int[] { 256 };
        float[] range = new float[] { 0f, 255f };
        bool accumulate = false;

        Mat b_hist = new Mat();
        Mat g_hist = new Mat();
        Mat r_hist = new Mat();

        CvInvoke.CalcHist(bgr_planes, dim, new Mat(), b_hist, histSize, range, accumulate);
        CvInvoke.CalcHist(bgr_planes, dim, new Mat(), g_hist, histSize, range, accumulate);
        CvInvoke.CalcHist(bgr_planes, dim, new Mat(), r_hist, histSize, range, accumulate);`

But I do not get Data b_hist, g_hist and r_hist. I can't address the specific channels bgr_planes[0], because those are of type Mat and it throws an error.

How can I adjust the parameters dim, histSize and range to get a color histogram?

Thank you so much for your help!

Upvotes: 0

Views: 1563

Answers (1)

Lea
Lea

Reputation: 31

I solved it myself (of course right after posting the question...):

Here is what I changed:

        Mat x = bgr_planes[0];

        Mat[] bVals = new Mat[1] { x };

        VectorOfMat colorChannelB = new VectorOfMat();

        colorChannelB.Push(bVals);

This separates one single color channel of the bgr_planes. In VectorOfMat colorChannelB is now only one color channel. Do that separately for every channel and keep the parameters.

Upvotes: 0

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